Process of transforming heat and of controlling working substances



Aug. 14, 1928. 1,680,453

R. W. DAVENPORT- PROCESS OF TRANSFORMING HEAT AND bl CONTROLLING WORKING SUBSTANCES Filed Dec. 22, 1925 I L E E A INVENTOK} 5 For/150m W Pave/300m /1/'$ ATTORNEY.

Patented Aug. 1 4, 1928.

UNITED STATES PATENT OFFICE.

RANSOM W. DAVENPORT, OF DETROIT, MICHIGAN, ASSIGN OR TO CHICAGO PNEUMATIC TOOL COMPANY, 01 NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS OF TBANSIORMING HEAT AND OF CONTROLLING WORKING SUBSTANCES.

Application filed December 22, 1925. Serial No. 77,156.

accomplished. It has particular application 5 to the production of refrigeration and to thermodynamic system's in which a working substance having liquid and vapor-gas comonents is operated through a closed cycle,

a n certain aspects the invention is of the :0 nature of an improvement upon and further development of the invention set forth in my copending application Ser. No. 15,172 filed March 12, 1925.

Among the objects of the invention are to rovide a new method of using gas-vaporiquid working substances, to utilize such working substances to produce refrigeration at a plurality of temperatures, to devise a new method of condensing such working substances, to develop a new method of feeding such working substances from the condenser to the evaporator, and in general to improve previous methods of effecting heat exchange. a

In conformity with my previous application above referred to the present invention contemplates the expansion of the vapor-gasliquid products of the condenser into a body of liquid refrigerant. The body of liquid is disposed in an elongate chamber or passage of restricted cross-sectional area and the sudden expansion thereinto of the vapor-gasliquid mixture causes a violent, rapid ebullition of the liquid which is prevented from circulating 'freelyby reason of its confinement and by its rapid agitation. The maximum refrigerating or heat absorbing effect is produced at the point of initial expansion but the body of'li uid in the elongate restricted expansion 0 amber continues to absorb heat throughout its length, but at progres sively higher temperatures as the top of the chamber is approached. The invention further provides for condensing the 45 vapor component of the gas-vapor mixture I discharged by the pump by providing a chamber of largevolume relative to the rate of discharge so that sufiicient time may be given for the vapor to reach condensing temperature and to disengage itself from the gas mixed therewith. The invention further provides for the simultaneous movement of the condensed liquid and of the uncondensed -gas and vapor from the condenser to the 5 evaporator.

In order to illustrate the invention one embodiment thereof is shown diagrammatically 1n the single view on the accompanying drawing. In the embodiment of the invention shown the refrigerating system, which s of the closed cycle type, comprises a compressor 1 discharging into a condenser 2 which has an outlet connection 3 extending to an expansion member 4 opening into an evaporator 5 supplied with a header or tank 6 from which extends a connection 7 to the compressor. The above elements are necessary to the practicing of the processes which form the subject matter of the present invention. l

The processes or steps in the major process involving the entire system will now be considered in detail. The compression step is erformed ,in the compressor 1 which Wit draws vapor and gas from the header 6 of the evaporator 5 and raising it to a predetermined pressure.

The condensing step is performed by discharging the vapor-gas mixture from the compressor 1 into condenser 2 which is in the form of a' hollow member or tank of such large volumei'elative to the rate of discharge therefrom that the vapor-gas mixture is contained therein for a considerable period of time. Heat is removed from the condenser by a suitable cooling medium passing over the exterior thereof. In the form shown this coolifigmedium is a vigor ous blast of air directed over the condenser by a fan 8 which may be mounted upon or driven by the prime mover for compressor 1, in the present instance an electric motor 9. The vapor when cooled to the condensing temperature condenses upon the walls of member 2, flowing down the same by gravity. The feeding and expanding step is performed by causing the condensate and the residual vapor-air mixture to pass simultaneously and in contiguity through pipe 3 into the expansion device 4 which may take the form of a restricted or Venturi opening of critical dimensions. In the arrangement shown in the drawinglthe condensate passes into pipe 3 by gravity forming a flowing lining for, the same while the residual gas and vapor pass down through the center.

The evaporating step is performed by causing the expanding liquid-.vapor-gas mixture from nozzle 4 to pass up through an elongate chamber of restricted size containmixture is removed by pump 1.

The apparatus shown to illustrate the invention is placed in operation by filling the member 5 with the liquid refrigerant and the members 6 and 2 with the vapor-gas component of the working substance and by starting pump 1. The total pressure in the header 6 is thus reduced as the total pressure in condenser 2 is raised and in consequence vapor and gas are removed from members 5 and 6 and compressed in member 2. The vapor is condensed in condenser 2 by 1 cooling the exterior thereof as by a blast of air from the fan 8 and the condensate and the vapor-gas component pass together through pipe 3 and nozzle 4 into; the coil or evaporator 5 which is positioned within the refrigerator. The expansion of the vapor-gas stream in intimate contact with the liquid results in a marked thermodynamic efi'ect manifested by a great drop in temperature and much absorption of heat. This effect continues in lessening degree as the gas continues to expand as it moves at a rapid rate up through the relatively small bore of member 5 releasing additional vapor from the liquid and violently agitating or emulsifying the same and some of the liquid is carried over into member 6. As the liquid is unable instantl to acquire saturation equilibrium with its vapor which is entangled in the gas, time is required before the temperature of the liquid can reach that corresponding to saturation pressure and during this time there is movement of the liquid on toward the member 6 and much interference with the back flow of the liquid due to the small bore of pipe 5 and to the continuous movement of the expanding gas therethrough. Due to this time lag the temperature in the lower part of the evaporator 5 tends to run lower than that of the upper part and in addition. heat is being a sorbed by the liquid throughout the length of evaporator 5. In consequence of the above factors the liquid in header 6 can be heated considerably warmer than the liquid adjacent the nozzle 4-. without effecting the temperature at the latter. As a result the density of the vapor taken into pump 1 from header 6 may be considerably greater than that corresponding with the lowest temperature in the refrigerator and may correspond more nearly with (the highest temperature therein. It is not essential to the practicing of the invention that the liquid and gaseous products of the condenser pass simulta- This neously and in contiguity through the expansion member 4 but the best results are se cured when the system operates in that manner.

From the member 6 the vapor and gas, the former compressed to the density corresponding with the warmer refrigerating, temperature, and the latter fully expanded, pass together into pump 1 where the total pressure of the mixture is raised. Upon discharging this compressed vapor-gas mixture into condenser 2 and upon removing heat from the surface thereof the vapor in contact with the inner surface condenses and .drains into pipe 3. It is essential that considerable time'be allowed for this step in order that the vapor may disentangle itself from the air; hence the use of the large tank form of condenser.

From the above it will be apparent that the present invention provides for heat absorption or pumping at a plurality of temperatures by the same refrigerating element, that the vapor of the liquid refrigerant may be removed at a temperature corresponding generally to the highest temperature in the chamber which is being cooled although the minimum or lowest temperature produced therein is far below, that the temperature of the refrigerating element tends to be a fixed variable with the lowest temperature obtaining at or adjacent the nozzle 4 and running progressively higher as the upper part of coil 5 is approached and ending with a temperature in the header or tank 6 corresponding generally to that of the refrigerator, that the new condensing method requires the simplest of apparatus including only a chamber of sufiicient volume to ermit the vapor-gas mixture to remain m a substantially static condition for a proper period of time while being acted upon by a cooling or heat removing medium, and that for best results the condensed liquid, residual vapor and gas from the condenser should pass simultaneously and in contiguity to and through the expansion device.

I claim as my invention:

1. The thermodynamic process of producing absorption of heat at a plurality of temperatures which comprises expanding a liquid-vapor-gas stream into a body of liquid and interfering with the equalizing in temperature in the liquid by restraining the free movement of the same while removing vapor from said body of liquid.

2. The thermodynamic process of producing absorption of heat at a plurality of temperatures which comprises expanding a liquid-vapor-gas stream through a restricted opening into a body of the liquid and confining the liquid in an elongate restricted chamber to prevent back flow and free circulation of the liquid while removing the vapor of said liquid.

3. The process of producing refrigeration which comprises confining a body of liquid refrigerant in an elongate restricted chamber forming a part of a closed cycle system, charging the system with a gas substantially inert to and insoluble in said liquid, withdrawing from the top of the chamber the vapor of the liquid, compressing the vapor thus Withdrawn together with the accompanying gas, condensing at least a part of the vapor, conducting the condensate together with the residual vapor and accompanying gas and expanding the same into said body of liquid thereby effecting absorption of heat at a plurality of temperatures by said body of liquid due to the inability of the liquid instantly to acquire saturation equilibriumwith its vapor and due to the interferences with the back flow of the liquid by its confinement and by the fast moving stream of expanding gas and vapor.

v4. In a thermodynamic process involving the continuous evaporating of liquid in a single vapor space, the art of preventing equalization of vapor pressures throughout said vapor space by moving thercthrough a current of inert and insoluble gas and restricting back flow of the liquid toward the incoming gas current.

Signed by me at Detroit, Vayne Co, Michigan, this 18th day of December. 1925.

RANSOM W. DAVENPORT. 

